One thing I like about this type of instrument is the company trademark, similar to the colophon of a publisher, that is stamped upon the accordion's metal corners. Sometimes it wasn't the company's trademark at all but a trademark designed for that particular model, or a badge designed for a particular retailer or dealer.
The Beaver Brand - some of these were built by Hohner.
A simple trademark used by Eagle Accordeon
Meinel und Herold sold rebadged accordions, as well as some that were produced independently.
Adolphus Professional Accordeon
International was a company in Germany that did nice work. This company built some of the nice Globe melodeons of the early 20th century.
"Royal Registered Accordion" -- the shape of this badge is the same as the shape as the Empress badge shown at the top of this post. Perhaps the same company is responsible for producing these two accordions?
I don't know which dealer or retailer the Milano line was built for, but in at least one example I have seen, the Koch company provided reed work (and probably built the rest of the accordion, as well).
Here is a corner from a Koch accordion, and below it is the adjustable screw mechanism that guaranteed the bellows seal was not compromised -- a good idea in an age of flimsy hair gaskets.
Pitzschler made some lavishly decorated accordions which restore nicely.
Ah, the familiar anchor trademark of the Kalbe company.
One of the badges used by Ludwig, featuring the famous pine tree.
Here is the Lyra badge, sold by Bruno and built in Germany.
This is a badge from Hohner, proclaiming it is the "Best Made," which isn't exactly true.
And another badge by Hohner. This colored portrait badge was used around 1905.
Ludwig made another accordion it called the Parsifal Melodeon. The player of a Parsifal had to be of pure heart in order to pick one up, or else he would turn to dust on the spot. History records several well known instances of this happening.
Two quite different badges by Universal Accordeon - one featuring wheels and one that looks like the badge of another company.
This interesting badge came from an accordion built in Spain and branded "Valencia - El Cid." It follows, then, that the man pictured on the horse is Charlton Heston.